Optical investigations on isovalent δ layers in III-V semiconductor compounds

Abstract

In contrast to usual quantum wells or barriers having a thickness of some lattice constants, spatially well-separated, electronically uncoupled monolayers of group-III or V elements are considered as isovalent δ doping or δ layers. Similar to the case of randomly distributed nitrogen dopants in GaP bulk material, it is shown that the two-dimensional arrangement of isovalent atoms brings forth a new quality of III-V semiconductor compounds: The optical emission and absorption properties near the fundamental band gap of indirect-gap, and even of direct-gap, host material, where the isovalent layers are incorporated, are drastically improved. Low-temperature luminescence and transmission experiments on metal-organic vapor-phase epitaxially grown InAs δ layers in GaAs, AlAs δ layers in GaAs, and GaAs monolayers in AlAs are dealt with.